1. Field of the Invention.
The present invention relates generally to treeshelters which are devices for covering and protecting seedlings and saplings. More specifically, the invention relates to treeshelter systems comprising a unitary shelter with integral staking means for securing the shelter in the ground surrounding the seedling or sapling. Treeshelters according to the invention are installed in a single step without tools and, once they are installed, they are extremely easy to remove and replace so that the seedling, sapling, or the like may be easily inspected. The removed shelter can be reused.
2. Description of the Prior Art
Treeshelters have long been recognized for their contribution to the growth and well-being of seedlings and saplings. Today, commercial treeshelter systems generally comprise a hollow tube with a circular or polygonal cross section, a separate support stake and connectors for securing the tube to the stake after it is pounded into the ground. Treeshelter systems of this type are thoroughly discussed in "TREESHELTERS", Handbook 7 of the UK Forestry Commission, by M. J. Potter. The U.S. Department of Agriculture and the Forest Service have published Keith Windell's document entitled "Tree Shelters For Seedling Protection" and it also discusses conventional treeshelter systems and their use.
Treeshelters protect young trees from damage due to wind and animals, while providing support for the young trees while they develop adequate root systems. They also enhance the growth rate of seedlings. Although the treeshelters protect seedlings against damage, they still permit sunshine and rain to nourish the seedlings, as well as permitting the application of chemical treatments including fertilizers and pesticides.
U.S. Pat. No. 4,899,486 discloses a conventional treeshelter comprising a twin walled extrusion in a cylindrical form. The patent also discloses that the treeshelter is installed by pounding a separate support stake in the ground, near a newly planted tree (with the risk of damage to the roots of the seedling) and securing the treeshelter to the separate support stake with several ties.
UK Patent application No. 2,212,048A discloses a treeshelter which comprises a separate support stake and a flexible sheet which is formed into a treeshelter shape, i.e., cylindrical, and retained in that shape by collars which include ties for securing the shelter to the support stake.
It is recognized by Potter, Windell and others that the use of these and other conventional multi-component treeshelter systems is very labor intensive and usually involves the use of a sledge hammer or heavy post driver for pounding a separate support stake in the ground. The installation of a treeshelter entails the delivery of the treeshelter components (shelter, separate support stake and ties) to the seedling site, pounding a separate support stake in the ground adjacent the seedling, positioning the shelter over the seedling and connecting the shelter with ties or the like to the separate support stake.
Conventional treeshelter systems are prone to failure in some cases, primarily for reasons involving the conventional, separate support stake. High winds can cause a shelter which is secured to a single, separate support stake to pivot about the stake to the extent that the shelter sheers off a seedling which it was designed to protect. Another failure mode for conventional treeshelters is breakage, usually around a knot, of the separate support stake while it is being pounded into the ground, especially in gravelly or rocky soil. Yet another failure mode involves rotting or degradation of the stake after the treeshelter has been installed. Although the separate support stake can be treated for weather resistance, the chemicals that are used to treat wood contain heavy metals which can leach from the support stake and harm the seedling.
Conventional treeshelters and the separate support stakes are pre-cut to various lengths and this contributes to problems with maintaining inventories of treeshelters and support stakes for various applications.
It is recognized that the growth rate of a seedling in a treeshelter which is taller than the seedling is relatively fast. The growth rate has been observed to decrease, however, when the top of the seedling reaches the top of the treeshelter. Accordingly, it would be advantageous to have a treeshelter system in which the height of a treeshelter could be extended simply and quickly. So far as is known, the height of conventional treeshelters can't be extended. A short conventional treeshelter system can be removed and replaced with a taller one, but that is very cumbersome.